Pivot and bearing assembly



Sept. 23, 1952 H. A. HADLEY PIVOT AND BEARING ASSEMBLY Filed March 7.1949 INVENTOR.

HARLAN A. HADLEY,

ATTORNEY Patented Sept. 23, 1952 PIVOT AND BEARING ASSEMBLY Harlan A.Hadley, Burlington, Vt., assignor to H. A. Hadley Associates, Inc.,Burlington, Vt., a corporation of Vermont Application March 7, 1949,Serial No. 80,025

12 Claims.

This invention relates to weighing scales, and relates more particularlyto a knife edge pivot and bearing assembly adapted for use in weighingscales.

This invention is a modification of the invention shown in myapplication Serial No. 73,270, filed January 28, 1949.

In many weighing mechanisms, levers are supported and the forces aretransmitted to and from the levers by means of knife edge pivot andbearing assemblies in which the knife edge pivot rests in a suitablymounted bearing provided with a V-groove. The V-groove normallypositions the pivot in a longitudinal plane and anti-friction platesapplied to the end of the bearing block normally restrain the pivot fromendwise motion. As is well known, such pivot and bearing assemblies arenot wholly satisfactory since their use leads to inaccuracies inweighing. Thus, since the V-groove must be made with a bottom having aslight radius to prevent frictional contact of the sides of the V-groovewith the sides of the knife edge pivot. the knife edge pivot skates overthe surface of the flattened bottom of the V-groove causing the lever toassume readily a different position for every different position of theknife edge pivot on the radius portion of the V-groove. The movement ofthe pivot relative to the radius portion of the V-groove alters thepivot distances, resulting in inaccuracies in the weighing.

It is an important object of this invention to provide an improved knifeedge pivot and bearing assembly which will be free from theabovementioned and other disadvantages and which will be especiallysimple in construction and emcient in use.

Another object of this invention is to provide a knife edge pivot andbearing assembly wherein the knife edge pivot cooperates with a fiatbearing surface and wherein the pivot and the bearing are connected toeach other to maintain the same in predetermined operative positionrelative to each other so that the pivot is free to turn on its normalaxis but is restrained from movement in any other direction.

A further object of this invention is to provide an improved flexuremember for holding the pivot and bearing in predetermined operativerelation to each other.

Still another object of this invention is the provision of a novelflexure member and support arrangement for holding the pivot and bearingin predetermined operative relation to each other.

Other objects of this invention, together with certain details ofconstruction and combinations of parts, will be apparent from thefollowing description and will be pointed out in the appended claims.

In the drawing, wherein a preferred embodiment of my invention is shown,

Figure 1 is a perspective view of my novel knife edge pivot and bearingassembly,

Figure 2 is a front elevational view thereof, and

Figure 3 is a side perspective view of a fiexure member.

Like reference numerals indicate like parts throughout the several viewsof the drawing.

Referring now to the drawing for a detailed description of my invention,the reference numeral 4 indicates a bearing block in which is imbedded abearing 5. The bearing 5 may be made of any suitable material ofsufiicient hardness. Preferably. the bearing is made of Norbide, acompound of boron and carbon, ground to optical flatness.

Knife edge 6 may be integral with knife edge block I, or may be suitablyheld therein; and is preferably made of Carboloy, tungsten-carbon alloy.However, the knife edge may be made of steel or any other suitablematerial.

In accordance with the present invention, the knife edge 6 is maintainedin proper position on the flat surface of bearing by means of a flexuremember or members generally indicated by reference numeral 8. Theflexure member comprises a pair of blocks 9 of any suitable metal, suchas brass, copper, steel, or the like, having fixed between them a web ofa resilient material II. While any suitable resilient material may beemployed, I prefer to use an elastomer such as natural or syntheticrubber. The rubber web II is suitably bonded or welded to the blocks 9.For greater sensitivity, the rubber web I I is cut away substantiallycentrally thereof, as is shown at I2, in such a manner that the smallestcross-section of the web is in line with the knife edge 6.

To maintain the flexure members 8 in position with respect to the knifeedge pivot and bearing assembly, each of the bearing blocks 4 and knifeedge blocks I are provided with projections I3 which may be integralwith their respective blocks. Flexure member supports I4 are attached tothe knife edge and bearing blocks by means of bolts or pins I5 and areeach provided with a seat I6 for the reception of the metallic blocks 9of the fiexure member. One of such supports I4 is mounted on bearingblock 4, with seat l6 facing downward, to one side of a vertical linepassing through the center of the ends of blocks 4 and I, while itscooperating support is mounted on knife edge block I, with its seat Itfacing upward, on the opposite side of said vertical line. A pair offiexure member supports may be similarly arranged on the other ends ofblocks 4 and I.

A flexure member 8 is attached to each cooperating pair of supports I4by means of screws I'I passing through openings I8 in the flexuremember. Thus, the flexure members are operatively fixed in the pivot andbearing assembly in a horizontal position with respect thereto, 1. e. ina plane coextensive with the plane of the surface of bearing 5.

The embodiment of my invention shown and described herein is to beconsidered merely as illustrative, as my invention is susceptible tovariation, modification and change within the spirit and scope of theappended claims.

I claim:

1. In a weighing scale having a pivot and bearing assembly, a flexuremember for restraining the movement of the pivot relative to thebearing, said flexure member comprising an elastomer web and a metalblock fixed to each end of said elastomer web and attached to said pivotand bearing assembly.

2. In a weighing scale having a pivot and bearing assembly, a flexuremember for restraining the movement of the pivot relative to thebearing, said flexure member comprising a rubber web and a metal blockfixed to each end of said rubber web and attached to said pivot andbearing assembly.

3. In a weighing scale having a pivot and bearing assembly, a flexuremember for restraining the movement of the pivot relative to thebearing. said flexure member comprising an elastomer web and a metalblock bonded to each end of said elastomer web and attached to saidpivot and bearing assembly.

4. In a weighing scale having a pivot and hearing assembly, a flexuremember for restraining the movement of the pivot relative to thebearing, said fiexure member comprising a rubber web and a metal blockbonded to each end of said rubber web and attached to said pivot andbearing assembly.

5. A pivot and bearing assembly for weighing scales, comprising a blockhaving a bearing surface, a block having a knife edge for engagementwith said bearing surface, a flexure member for restraining the movementof said knife edge relative to said bearing surface, said flexure membercomprising an elastomer web and a metal block fixed to each end of saidelastomer Web, and means carried by said bearing surface and knife edgeblocks for supporting the metal blocks fixed to said elastomer web inoperative position.

6. A pivot and bearing assembly for weighing scales, comprising a blockhaving a bearing surface, a block having a knife edge for engagementwith said bearing surface, a fiexure member for restraining the movementof said knife edge re-lative to said bearing surface, said flexuremember comprising an elastomer web, having a reduced cross-sectionsubstantially centrally thereof. and a metal block bonded to each end ofsaid elastomer web, and means carried by said hear-- ing surface andknife edge blocks for supporting the metal blocks bonded to saidelastomer web in operative position.

'7. A pivot and bearing assembly for weighing scales comprising a blockhaving a bearing surface, a block having a knife edge for engagementwith said bearing surface, a flexure member, said flexure membercomprising a rubber web, having a reduced cross section substantiallycentrally thereof, and a metal block bonded to each end of said rubberweb, and means carried by said bearing surface and knife edge blocks forsupporting the metal blocks bonded to said rubber web in operativeposition.

8. A pivot and bearing assembly for weighing scales, comprising a blockhaving a bearing surface, a block having a knife edge for engagementwith said bearing surface, two projections carried by each of saidblocks, and flexure members supported by said projections forrestraining the movement of said knife edge relative to said bearingsurface, each of said fiexure members comprising an elastomer web and ametal block bonded to each end of said elastomer web.

9. A pivot and bearing assembly for weighing scales, comprising a blockhaving a bearing surface, a block having a knife edge for engagementwith said bearing surface, two projections carried by each of saidblocks, and flexure members supported by said projections forrestraining the movement of said knife edge relative to said bearingsurface, each of said fiexure members comprising a rubber web and ametal block bonded to each end of said rubber web.

10. A pivot and bearing assembly for weighing scales, comprising a blockhaving a bearing surface, a block having a knife edge for engagementwith said bearing surface, two projections carried by each of saidblocks, and fiexure members supported by said projections forrestraining the movement of said knife edge relative to said bearingsurface, each of said flexure members comprising a. rubber web, having areduced crosssection substantially centrally thereof, and a metal blockbonded to each end of said rubber We 11. A pivot and bearing assemblyfor weighing scales, comprising a block having a bearing sin"- face, ablock having a knife edge for engagement with said bearing surface, twoprojections carried by each of said blocks, and flexure memberssupported by said projections for restraining the movement of said knifeedge relative tosaid bearing surface, each of said fiexure memberscomprising a rubber web and a metal block bonded to each end of saidrubber web, the construction and arrangement being such that the fiexuremembers are supported by said projections in a plane substantiallycoextensive with the plane of said bearing surface.

12. A pivot and bearing assembly for weighing scales, comprising a blockhaving a bearing surface, a block having a knife edge for engagementwith said bearing surface, two projections carried by each of saidblocks, and flexure members supported by said projections forrestraining the movement of said knife edge relative to said bearingsurface, each of said flexure members comprising a rubber web, having areduced cross-section substantially centrally thereof, and a metal blockbonded to each end of said rubber web, the construction and arrangementbeing such that the fiexure members are supported by said projections ina plane substantially coextensive with the plane of said bearingsurface.

HARLAN A. HADLEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 392,617 Lieb Nov. 13, 18881,071,761 Leake Sept. 2, 1913 2,458,537 Skelly a. Jan. 11, 1949

